We have used in situ hybridization and immunocytochemistry to map the cellular patterns of expression for elements of the IGE system and functionally-related molecules such as the recently characterized family of facilitative glucose transporters - in both rodent and human nervous, renal and reproductive systems. The data resulting from these studies have provided important new information on the roles of these growth factors and their numerous different binding proteins in the regulation of normal developmental processes and in tissue-specific responses to physiologic stress and pathologic injury.